test/vpp_pg_interface.py

   1 import os
   2 import time
   3 import socket
   4 from traceback import format_exc
   5 from scapy.utils import wrpcap, rdpcap, PcapReader
   6 from vpp_interface import VppInterface
   7
   8 from scapy.layers.l2 import Ether, ARP
   9 from scapy.layers.inet6 import IPv6, ICMPv6ND_NS, ICMPv6ND_NA,\
  10     ICMPv6NDOptSrcLLAddr, ICMPv6NDOptDstLLAddr, ICMPv6ND_RA, RouterAlert, \
  11     IPv6ExtHdrHopByHop
  12 from util import ppp, ppc
  13 from scapy.utils6 import in6_getnsma, in6_getnsmac, in6_ismaddr
  14 from scapy.utils import inet_pton, inet_ntop
  15
  16
  17 def is_ipv6_misc(p):
  18     """ Is packet one of uninteresting IPv6 broadcasts? """
  19     if p.haslayer(ICMPv6ND_RA):
  20         if in6_ismaddr(p[IPv6].dst):
  21             return True
  22     if p.haslayer(IPv6ExtHdrHopByHop):
  23         for o in p[IPv6ExtHdrHopByHop].options:
  24             if isinstance(o, RouterAlert):
  25                 return True
  26     return False
  27
  28
  29 class VppPGInterface(VppInterface):
  30     """
  31     VPP packet-generator interface
  32     """
  33
  34     @property
  35     def pg_index(self):
  36         """packet-generator interface index assigned by VPP"""
  37         return self._pg_index
  38
  39     @property
  40     def out_path(self):
  41         """pcap file path - captured packets"""
  42         return self._out_path
  43
  44     @property
  45     def in_path(self):
  46         """ pcap file path - injected packets"""
  47         return self._in_path
  48
  49     @property
  50     def capture_cli(self):
  51         """CLI string to start capture on this interface"""
  52         return self._capture_cli
  53
  54     @property
  55     def cap_name(self):
  56         """capture name for this interface"""
  57         return self._cap_name
  58
  59     @property
  60     def input_cli(self):
  61         """CLI string to load the injected packets"""
  62         return self._input_cli
  63
  64     @property
  65     def in_history_counter(self):
  66         """Self-incrementing counter used when renaming old pcap files"""
  67         v = self._in_history_counter
  68         self._in_history_counter += 1
  69         return v
  70
  71     @property
  72     def out_history_counter(self):
  73         """Self-incrementing counter used when renaming old pcap files"""
  74         v = self._out_history_counter
  75         self._out_history_counter += 1
  76         return v
  77
  78     def __init__(self, test, pg_index):
  79         """ Create VPP packet-generator interface """
  80         r = test.vapi.pg_create_interface(pg_index)
  81         self._sw_if_index = r.sw_if_index
  82
  83         super(VppPGInterface, self).__init__(test)
  84
  85         self._in_history_counter = 0
  86         self._out_history_counter = 0
  87         self._pg_index = pg_index
  88         self._out_file = "pg%u_out.pcap" % self.pg_index
  89         self._out_path = self.test.tempdir + "/" + self._out_file
  90         self._in_file = "pg%u_in.pcap" % self.pg_index
  91         self._in_path = self.test.tempdir + "/" + self._in_file
  92         self._capture_cli = "packet-generator capture pg%u pcap %s" % (
  93             self.pg_index, self.out_path)
  94         self._cap_name = "pcap%u" % self.sw_if_index
  95         self._input_cli = \
  96             "packet-generator new pcap %s source pg%u name %s" % (
  97                 self.in_path, self.pg_index, self.cap_name)
  98
  99     def enable_capture(self):
 100         """ Enable capture on this packet-generator interface"""
 101         try:
 102             if os.path.isfile(self.out_path):
 103                 os.rename(self.out_path,
 104                           "%s/history.[timestamp:%f].[%s-counter:%04d].%s" %
 105                           (self.test.tempdir,
 106                            time.time(),
 107                            self.name,
 108                            self.out_history_counter,
 109                            self._out_file))
 110         except:
 111             pass
 112         # FIXME this should be an API, but no such exists atm
 113         self.test.vapi.cli(self.capture_cli)
 114         self._pcap_reader = None
 115
 116     def add_stream(self, pkts):
 117         """
 118         Add a stream of packets to this packet-generator
 119
 120         :param pkts: iterable packets
 121
 122         """
 123         try:
 124             if os.path.isfile(self.in_path):
 125                 os.rename(self.in_path,
 126                           "%s/history.[timestamp:%f].[%s-counter:%04d].%s" %
 127                           (self.test.tempdir,
 128                            time.time(),
 129                            self.name,
 130                            self.in_history_counter,
 131                            self._in_file))
 132         except:
 133             pass
 134         wrpcap(self.in_path, pkts)
 135         self.test.register_capture(self.cap_name)
 136         # FIXME this should be an API, but no such exists atm
 137         self.test.vapi.cli(self.input_cli)
 138
 139     def _get_capture(self, timeout, filter_out_fn=is_ipv6_misc):
 140         """ Helper method to get capture and filter it """
 141         try:
 142             if not self.wait_for_capture_file(timeout):
 143                 return None
 144             output = rdpcap(self.out_path)
 145             self.test.logger.debug("Capture has %s packets" % len(output.res))
 146         except:
 147             self.test.logger.debug("Exception in scapy.rdpcap (%s): %s" %
 148                                    (self.out_path, format_exc()))
 149             return None
 150         before = len(output.res)
 151         if filter_out_fn:
 152             output.res = [p for p in output.res if not filter_out_fn(p)]
 153         removed = len(output.res) - before
 154         if removed:
 155             self.test.logger.debug(
 156                 "Filtered out %s packets from capture (returning %s)" %
 157                 (removed, len(output.res)))
 158         return output
 159
 160     def get_capture(self, expected_count=None, remark=None, timeout=1,
 161                     filter_out_fn=is_ipv6_misc):
 162         """ Get captured packets
 163
 164         :param expected_count: expected number of packets to capture, if None,
 165                                then self.test.packet_count_for_dst_pg_idx is
 166                                used to lookup the expected count
 167         :param remark: remark printed into debug logs
 168         :param timeout: how long to wait for packets
 169         :param filter_out_fn: filter applied to each packet, packets for which
 170                               the filter returns True are removed from capture
 171         :returns: iterable packets
 172         """
 173         remaining_time = timeout
 174         capture = None
 175         name = self.name if remark is None else "%s (%s)" % (self.name, remark)
 176         based_on = "based on provided argument"
 177         if expected_count is None:
 178             expected_count = \
 179                 self.test.get_packet_count_for_if_idx(self.sw_if_index)
 180             based_on = "based on stored packet_infos"
 181             if expected_count == 0:
 182                 raise Exception(
 183                     "Internal error, expected packet count for %s is 0!" %
 184                     name)
 185         self.test.logger.debug("Expecting to capture %s (%s) packets on %s" % (
 186             expected_count, based_on, name))
 187         if expected_count == 0:
 188             raise Exception(
 189                 "Internal error, expected packet count for %s is 0!" % name)
 190         while remaining_time > 0:
 191             before = time.time()
 192             capture = self._get_capture(remaining_time, filter_out_fn)
 193             elapsed_time = time.time() - before
 194             if capture:
 195                 if len(capture.res) == expected_count:
 196                     # bingo, got the packets we expected
 197                     return capture
 198             remaining_time -= elapsed_time
 199         if capture:
 200             raise Exception("Captured packets mismatch, captured %s packets, "
 201                             "expected %s packets on %s" %
 202                             (len(capture.res), expected_count, name))
 203         else:
 204             raise Exception("No packets captured on %s" % name)
 205
 206     def assert_nothing_captured(self, remark=None, filter_out_fn=is_ipv6_misc):
 207         """ Assert that nothing unfiltered was captured on interface
 208
 209         :param remark: remark printed into debug logs
 210         :param filter_out_fn: filter applied to each packet, packets for which
 211                               the filter returns True are removed from capture
 212         """
 213         if os.path.isfile(self.out_path):
 214             try:
 215                 capture = self.get_capture(
 216                     0, remark=remark, filter_out_fn=filter_out_fn)
 217                 if not capture:
 218                     # junk filtered out, we're good
 219                     return
 220                 self.test.logger.error(
 221                     ppc("Unexpected packets captured:", capture))
 222             except:
 223                 pass
 224             if remark:
 225                 raise AssertionError(
 226                     "Non-empty capture file present for interface %s (%s)" %
 227                     (self.name, remark))
 228             else:
 229                 raise AssertionError("Capture file present for interface %s" %
 230                                      self.name)
 231
 232     def wait_for_capture_file(self, timeout=1):
 233         """
 234         Wait until pcap capture file appears
 235
 236         :param timeout: How long to wait for the packet (default 1s)
 237
 238         :returns: True/False if the file is present or appears within timeout
 239         """
 240         limit = time.time() + timeout
 241         if not os.path.isfile(self.out_path):
 242             self.test.logger.debug("Waiting for capture file %s to appear, "
 243                                    "timeout is %ss" % (self.out_path, timeout))
 244         else:
 245             self.test.logger.debug(
 246                 "Capture file %s already exists" %
 247                 self.out_path)
 248             return True
 249         while time.time() < limit:
 250             if os.path.isfile(self.out_path):
 251                 break
 252             time.sleep(0)  # yield
 253         if os.path.isfile(self.out_path):
 254             self.test.logger.debug("Capture file appeared after %fs" %
 255                                    (time.time() - (limit - timeout)))
 256         else:
 257             self.test.logger.debug("Timeout - capture file still nowhere")
 258             return False
 259         return True
 260
 261     def wait_for_packet(self, timeout, filter_out_fn=is_ipv6_misc):
 262         """
 263         Wait for next packet captured with a timeout
 264
 265         :param timeout: How long to wait for the packet
 266
 267         :returns: Captured packet if no packet arrived within timeout
 268         :raises Exception: if no packet arrives within timeout
 269         """
 270         deadline = time.time() + timeout
 271         if self._pcap_reader is None:
 272             if not self.wait_for_capture_file(timeout):
 273                 raise Exception("Capture file %s did not appear within "
 274                                 "timeout" % self.out_path)
 275             while time.time() < deadline:
 276                 try:
 277                     self._pcap_reader = PcapReader(self.out_path)
 278                     break
 279                 except:
 280                     self.test.logger.debug(
 281                         "Exception in scapy.PcapReader(%s): "
 282                         "%s" %
 283                         (self.out_path, format_exc()))
 284         if not self._pcap_reader:
 285             raise Exception("Capture file %s did not appear within "
 286                             "timeout" % self.out_path)
 287
 288         self.test.logger.debug("Waiting for packet")
 289         while time.time() < deadline:
 290             p = self._pcap_reader.recv()
 291             if p is not None:
 292                 if filter_out_fn is not None and filter_out_fn(p):
 293                     self.test.logger.debug(
 294                         "Packet received after %ss was filtered out" %
 295                         (time.time() - (deadline - timeout)))
 296                 else:
 297                     self.test.logger.debug(
 298                         "Packet received after %fs" %
 299                         (time.time() - (deadline - timeout)))
 300                     return p
 301             time.sleep(0)  # yield
 302         self.test.logger.debug("Timeout - no packets received")
 303         raise Exception("Packet didn't arrive within timeout")
 304
 305     def create_arp_req(self):
 306         """Create ARP request applicable for this interface"""
 307         return (Ether(dst="ff:ff:ff:ff:ff:ff", src=self.remote_mac) /
 308                 ARP(op=ARP.who_has, pdst=self.local_ip4,
 309                     psrc=self.remote_ip4, hwsrc=self.remote_mac))
 310
 311     def create_ndp_req(self):
 312         """Create NDP - NS applicable for this interface"""
 313         nsma = in6_getnsma(inet_pton(socket.AF_INET6, self.local_ip6))
 314         d = inet_ntop(socket.AF_INET6, nsma)
 315
 316         return (Ether(dst=in6_getnsmac(nsma)) /
 317                 IPv6(dst=d, src=self.remote_ip6) /
 318                 ICMPv6ND_NS(tgt=self.local_ip6) /
 319                 ICMPv6NDOptSrcLLAddr(lladdr=self.remote_mac))
 320
 321     def resolve_arp(self, pg_interface=None):
 322         """Resolve ARP using provided packet-generator interface
 323
 324         :param pg_interface: interface used to resolve, if None then this
 325             interface is used
 326
 327         """
 328         if pg_interface is None:
 329             pg_interface = self
 330         self.test.logger.info("Sending ARP request for %s on port %s" %
 331                               (self.local_ip4, pg_interface.name))
 332         arp_req = self.create_arp_req()
 333         pg_interface.add_stream(arp_req)
 334         pg_interface.enable_capture()
 335         self.test.pg_start()
 336         self.test.logger.info(self.test.vapi.cli("show trace"))
 337         try:
 338             captured_packet = pg_interface.wait_for_packet(1)
 339         except:
 340             self.test.logger.info("No ARP received on port %s" %
 341                                   pg_interface.name)
 342             return
 343         arp_reply = captured_packet.copy()  # keep original for exception
 344         # Make Dot1AD packet content recognizable to scapy
 345         if arp_reply.type == 0x88a8:
 346             arp_reply.type = 0x8100
 347             arp_reply = Ether(str(arp_reply))
 348         try:
 349             if arp_reply[ARP].op == ARP.is_at:
 350                 self.test.logger.info("VPP %s MAC address is %s " %
 351                                       (self.name, arp_reply[ARP].hwsrc))
 352                 self._local_mac = arp_reply[ARP].hwsrc
 353             else:
 354                 self.test.logger.info("No ARP received on port %s" %
 355                                       pg_interface.name)
 356         except:
 357             self.test.logger.error(
 358                 ppp("Unexpected response to ARP request:", captured_packet))
 359             raise
 360
 361     def resolve_ndp(self, pg_interface=None, timeout=1):
 362         """Resolve NDP using provided packet-generator interface
 363
 364         :param pg_interface: interface used to resolve, if None then this
 365             interface is used
 366         :param timeout: how long to wait for response before giving up
 367
 368         """
 369         if pg_interface is None:
 370             pg_interface = self
 371         self.test.logger.info("Sending NDP request for %s on port %s" %
 372                               (self.local_ip6, pg_interface.name))
 373         ndp_req = self.create_ndp_req()
 374         pg_interface.add_stream(ndp_req)
 375         pg_interface.enable_capture()
 376         self.test.pg_start()
 377         now = time.time()
 378         deadline = now + timeout
 379         # Enabling IPv6 on an interface can generate more than the
 380         # ND reply we are looking for (namely MLD). So loop through
 381         # the replies to look for want we want.
 382         while now < deadline:
 383             try:
 384                 captured_packet = pg_interface.wait_for_packet(
 385                     deadline - now, filter_out_fn=None)
 386             except:
 387                 self.test.logger.error(
 388                     "Timeout while waiting for NDP response")
 389                 raise
 390             ndp_reply = captured_packet.copy()  # keep original for exception
 391             # Make Dot1AD packet content recognizable to scapy
 392             if ndp_reply.type == 0x88a8:
 393                 ndp_reply.type = 0x8100
 394                 ndp_reply = Ether(str(ndp_reply))
 395             try:
 396                 ndp_na = ndp_reply[ICMPv6ND_NA]
 397                 opt = ndp_na[ICMPv6NDOptDstLLAddr]
 398                 self.test.logger.info("VPP %s MAC address is %s " %
 399                                       (self.name, opt.lladdr))
 400                 self._local_mac = opt.lladdr
 401                 self.test.logger.debug(self.test.vapi.cli("show trace"))
 402                 # we now have the MAC we've been after
 403                 return
 404             except:
 405                 self.test.logger.info(
 406                     ppp("Unexpected response to NDP request:",
 407                         captured_packet))
 408             now = time.time()
 409
 410         self.test.logger.debug(self.test.vapi.cli("show trace"))
 411         raise Exception("Timeout while waiting for NDP response")